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Re: Gap Dwell Times (formerly: Beating Solved)



Some measurements captured on the storage scope from my coil (just 
now):

Calculated spec : k around 0.12  (from dF/F)

Measured : f = 146.5kHz
Tdwell around 25uS (time to max sec ringup, pri ringdown to near zero)
Envelope time (ringup+ringdown for one complete envelope) about 50uS
Cycles during Tdwell = 3.5  (7 half cycles)

Blowing compressed air through the gap made no noticeable difference
but the gap discharge got much "snappier" and noisy.

Primary Alone:   Cap = 0.1uF, Lp 11.8uH   Times are +- 5uS

Cap Voltage    Cap Energy   Rings   Dwell Time  Q (from decr. calc)
2kV            200mJ        15       100uS        8.6 
5kV            1.25J        19       130uS       10.2
8kV            3.2J         21       150uS        8.1
10kV           5J           22       155uS        8.9
12kV           7.2J         23       160uS        10.3

Re - Q : because of artifacts adding some randomness to the waveform
it was difficult to get exact peak readings. I haven't attempted to
dress the figures up in any way, but I think you can see the trends.
Accuracy for Q about +-1

Blasting air through the gap at 10kV cut it off at 140uS. Discharge 
very loud and sharp. I'm sorry I don't know what the pressure was but
it is an industrial compressed air source blown through a fine nozzle.
This was rather dangerous but a quick way of checking. Not advised.

     Hopefully this will answer one or two questions.
     
Malcolm